Carburetor for internal-combustion engines



June 10, 1924. 1,497,480 G. F. BULL. ET AL CARBURETOR FOR INTERNAL COMBUSTION ENGINES Filed Jan. 2 1920 3 Sheets-Sheet 1 June no, 1924., 1,497,480

G. F. BULL ET AL CARBURETOR FOR INTERNAL COMBUSTION ENGINES Filed Jan. 2, 1920 3 SneetvSheei 2 June 10, 1924. 1,497,480

G. F. BULL ET AL CARBURETOR FOR INTERNAL COMBUSTION ENGINES Filed Jan. 2 1920 s sheets sneez 5 Patented June 10, 1924.

UNIT

1,497,480 is as.

"aeoaesram mm BU L AND ERNEST WALTER STARKEY, or BIRMINGHAM-13km "LAND; SAID STARKEY ASSIGNOR To CHARLES H. PUGI-I LIMITED, or BIRMING- ENGLAND.

cAfaBUnETon roe INTERNAL-COMBUSTION ENGINES.

Application filed January 2, 1920. Serial No. 349,001.

Tecll whom it may concern: Beit known that GEORGE FREDERICK BULL a-nd ERNns'r WALTER STARKEY, subjects of the Kingof Great Britain, residing at Small Heath, Birmingham, England, have invented certain new anduseful Improvements in Carburetorsfor Internal-Combustion Engines, of which the. following is a specification. 7

- Thisinvention relates to carburetors for internal combustion engines, of the kind in {which air'is drawnpast the fuel jet through an atomizing tube situated in the main air inlet, the fuel being atomized by the air passing. through the atomizing tube and mixing with the main air supply drawn through the main air inlet.

Withthis construction of carburetor it is found,v that for the lower ranges of speed the mixture is too rich unless the throttle valveis provided with an opening therein especial-1y shaped to suit the particular kind of engine with which the carburetoris associated. The" principal object, therefore, of the present. invention is to provide means for obtaining a correct mixture for starting and slow-running without the necessity of specially shaping the throttle valve for different engines.

According to the invention, the throttle valve is provided with a slot which is arranged to come opposite the atomizing tube at small throttle openings, while the said atomizing tube is provided upon the throttle side of the nozzle, with jet-damping air passages which reduce the suction on the nozzle at slow speeds, and these damping passages are situated in the constricted portion ofthe main air intake passage of the carburetor so that at low speeds air is taken through; these holes from the main air passagea d reducesthe, suction on the nozzle, enemas when; the throttle is vopened the effect of these damping passages is automatiifitilllii ili out or suppressed without the use "ofany moving parts. To regulate the richbfthe;-mixture to suit requirements e se the damperholes is adapted to be var d by means of 'a regulating sleeve.

- V Figure; 1 of the accompanying drawing esents a vertical longitudinal 7 section essay in elevation of a carburetor constructed in accordance with the present in vention. v p

Figure 2 is an end view of the,same:,- i Figure 3 represents a horizontal section through the atomizing tube. i s Figures 4 and 5 are transverse sections through the jet damping apertures of the atomizing tube and through the regulating sleeveishowing how the regulating of the mixture is effected. Figure 5 is a detail view on a larger scale, of a portion of Figure .1 shes ingest upper end of the fuel nozzlatheeonjstriaed portion 6 and the atomizingitu-be and: the sleeve surrounding the latter being g teway in a vertical plane between said nozzle and the barrel valve.

, Figure 6 is a section through a vertical type of carburetor constructed according to the present invention.

Figure 7 represents a cross section through the atomizing tube and regulator.

Figures 8 to 10 show modifications.

Referring to Figures 1 to 6, the nozzle l is arranged vertically and being s'uppo rted by the bracket 15 carried by the floatchamber 16 extends into the bore of 'a horizontal atomizing tube 2 which is rotatably mounted within an outer. regulatingsleeve scarried by transverse web 4 crossing the main air inlet 5, the inner ends of the atomizing tube and regulating sleeve extendingintothe constricted portion 6 ofrthe air inlet passage adjacent to thebarrel-t'ypethrottle valve 7. The atomizing tube 2 is provided, upon the throttle side of the nozzle, with jet-damping apertures 8, 8 adapted. to, be

air in the constricted portionfi surrounding the atomizer is of low velocity, due to the depression at that point being small. Consequently air is caused to pass from the constricted portion of the main air inlet passage through the damper holes 8, 9, into the atomizer tube on the engine side of the nozzle, thereby reducing the depression about the nozzle and diminishing the supply of fuel. As the throttle is opened, and the speed of the engine increases, the depression in the air passage around the atomizer tube 2 becomes greater, and the flow of air through the damper holes 8, 9, is diminished, until a point i reached when the depression outside the atomizer tube is equal to that within the said tube, so that no air passes through the damper holes, and consequently there is no restriction on the flow of fuel from the nozzle, which can be of large size in order to supplythe full quantity of fuel required with'wide throttle openings, the

supply being automatically reduced by the damper holes as the throttle is closed and thespeed decreases.

To adjust the quantity of fuel delivered at low speeds for a given engine, or for a .given set of conditions, the effective size of the damper holes can be increased or de creased by rotating the atomizer tube 2 within the interior of the fixed outer regir l'ator sleeve 3, so as to cause the apertures 8, 9, to register more or less as required.

The rotatable atomizer tube 2 is slotted at spring-plunger13 engaging the knurled periphery. [Two stop pins 14,14, determine the rangeof adjustment. Once the richness of the mixture has been determined for a given set of conditions, it is not necessary to alter the regulator unless those conditions vary.

In the application of the invention to the vertical type of carburetor shown in Figures 6 and 7, the atomizer tube 2 is arranged vertically and is mounted upon a bracket 15 carried by the float chamber 16, said tube 2 being provided with a central vertical bore 17 for the passage of the atomizing air, and its upper end extending into the intake port of the barrel-type throttle valve 7. At a suitable point in the tube is a petrol nozzle 1 extendinginto the tube in a horizontal direction, said nozzle being screwed into a hole in the side of the atomizer so that its bore communicates with a vertical fuel passage 18 drilled through the body of the atomizer tube. At the lower end of the latter this fuel passage enters a groove 19 communicating with a passage in the carrier bracket leading from the float chamber.

The atomizer tube is situated within the constricted portion 6 of the intake passage,

so that when the throttle is opened a main supply of air is drawn through-said airinlet and throttle and around the atomizer. The latter is provided, above the nozzle but below the throttle, with two or other suit able number of inclined nozzle-damping air passages 8, 8, situated within the constricted portion 6 and leading therefrom to the interior of the bore. hen the throttle is nearly closed the inner end of the atomizer tube 2 is opposite the slot 10 in one side of the intake port of the barrel type throttle valve 7 and remains opposite said slot throughout a range of movement, until the main area of the intake port comes opposite to said atomizer. During the initial opening stages of the throttle the depression created by the engine is practically wholly concentrated on the atomizer tube 2, whilst the flow of air in the constricted portion 6 surrounding the atomizer is of low velocity, due to the depression at that point being small. Consequently air is caused to pass from the constricted portion 6 through the damper holes 8, 9, into the atomizer tube on the engine side of the jet, thereby reducing the depression about the jet and diminishing the supply of fuel. As the throttle is opened, and the speed of the engine increases, the depression in the constricted portion (3 around the atomizer tube 2 becomes greater, and the flow of air through the" damper holes 8 is diminished until a point is reached when the depression outside the atomizer tube is equal to that within the said tube, so that no air passes through the damper holes, and consequently thereis no restriction on the flow of fuel from the jet, which can be of large size in order to supply the full quantity of fuel required with wide throttle openings, the supply being automatically reduced by the damper holes as the throttle is closed and the speed decreases.

In order to regulate the richness of the mixture, the damping passages 8 in the wall of the atomizer tube maybe controlled by means of a rotatable sleeve 3 surrounding said tube and having suitable openings or cut-away parts 9 corresponding to the passages 8, so that by partially rotating the sleeve into different angular positions the said damping passages may be more or less closed according to requirements. The sleeve 3 may conveniently carry an operating arm or lever 20 provided with apointer 21 adapted to serve as an indicator of the degree of richness of the mixture.

Or, instead of a rotatable sleeve, a sliding sleeve may be employed.

In the modification represented in Figure 8, the vertical nozzle 1 extends through the lower open end of a vertical and con-' constricted portion 6 of the main air inlet adjacent to a barrel-type throttle valve 7. The upper portion of the tube 2, above the nozzle, is reduced in diameter, as shown, and a current of air is drawn, by the engine, through the said tube and past the nozzle, serving thoroughly to break-u and atomize the fuel which issues from tie nozzle, the sprayed fuel, during normal running, mixing with an extra supply of air passing around the outside of the tube 2. The said atomizer tube 2 is provided with nozzledamping apertures 8 situated within the constricted portion 6, the size of these apertures being adapted to be adjusted by means of a rotatable regulating sleeve 3 having apertures 9 which can be brought more or less into register with the apertures 8.

As in the previous arrangements, when the throttle valve is nearly closed the end of the tube 2 is opposite to a slot or slow-running aperture in one side of the intake port of the throttle valve, and remains opposite this slot throughout a rangeof movement, until the main area of the intake port comes opposite to said atomizer tube. During the initial opening stages of the throttle the depression created by the en ine is practically wholly concentrated on the atomizer tube, whilst the flow of air in the constricted portion 6 surrounding the atomizer is of low velocity, due to the depression at that point being small. Consequently air is caused to pass from the constricted portion 6 through the damper holes 8 into the atomizer tube on the engine side of the nozzle, thereby reducing the depression about the nozzle and di minishin the supply of fuel. As the throttle is openec and the speed of the engine increases, the depression in the constricted air passage around the atomizer tube 2 becomes greater, and the flow of air through the damper 'holes 8 is diminished, until a point is reached when the depression outside the atomizer tube is equal to that within said tube, so that no air passes through the damper holes, and consequently there is no restriction on the flow of fuel from the nozzle.

In the modifications of the invention represented in Figures 9 and 10 the operation in so far as the throttle valve and the dampening apertures 8 are concerned is identical with that of the forms shown in Figure 8 and in the previously described modifications. In each of said figures the lower end of the atomizer tube is shown as being closed by the liquid fuel nozzle 1 so that other provision must be made for the normal admission of atomizing air of the atomizer tube. This is accomplished by the ports 19 which provide communication between the interior of the atomizer tube and with the main air inlet tube opening into the latter at a point where it is more or less unrestricted and therefore being not subject to the dampening effect of the throttle valve, in certain positions as are the dampening apertures 8. The distinction between figures 9 and 10 lies in the disclosure of the former figure. The atomizing air inlet apertures 19 are placed some distance back of the mouth of the nozzle 1., while in Figure 10 they are shown about flush with the end of said nozzle. In both figures an external sleeve 3 surrounds the atomizer tube having apertures 9 and 20 aligning respectively with the dampening and atomizing air in the apertures, and by means of which the effect of area of both said apertures may be varied at will by turning the sleeve 3. The effect of this adjustment upon the atomizing air in the apertures is to give a richer or leaner mixture over a whole range of throttle openings.

Having fully described our invention, whatwe desire to claim and secure by Letters Patent is 1. A carburetor comprising main and atomizing air tubes, communicating with the fuel intake of an internal combustion engine, a liquid fuel nozzle opening into said atomizing air tube, a throttle valve controlling the communication of said air tubes with said engine intake, said throttle valve being provided with ports so disposed as, in one position of the valve, to close the main air tube leaving the atomizing air tube open to the engine intake, and in another position of said valve, to leave both tubes open to the engine intake, and nozzle dampening air passages in the wall of said atomizing air tube between the nozzle and throttle valve and communicating with the main air tube.

2. A carburetor comprising a main airinlet having a constricted part, a rotatable atomizing tube in the main air-inlet, a throttle valve having a slot which comes opposite the atomizing tube at small throttle openings, a fuel nozzle extending into the atomizing tube, and an outer fixed sleeve supporting the atomizing tube, said atomizing tube having nozzle damping apertures situated between the jet and the throttle and in the constricted part of the main airinlet, and the outer sleeve having apertures adapted to be brought more or less into register with the nozzle-damping apertures.

In testimony whereof we have hereunto set our hands in presence of two subscribing witnesses.

GEORGE FREDERICK BULL.

ERNEST WALTER STARKEY. Witnesses;

A. N. MEBRETT,

H. O. PRATT. 

